A composite lining structure for underground gas storage chambers

Abstract

This invention discloses a composite lining structure for underground gas storage chambers, belonging to the field of underground gas storage engineering technology. The structure, from the internal cavity of the chamber outwards, comprises a steel lining sealing layer, a concrete lining layer, a sliding layer, and a shotcrete layer. The concrete lining layer contains several polyurethane sealants to improve the structure's compressive strength and durability. The polyurethane sealants are preferably made of rigid polyurethane foam, which can be cast on-site or prefabricated, and are evenly distributed circumferentially within the concrete lining layer, such as six sealants. The sliding layer uses a composite asphalt-based material, allowing relative displacement between the concrete lining layer and the shotcrete layer to reduce stress concentration. This structure, through optimized materials and layout, significantly improves the sealing performance, compressive strength, and fatigue resistance of the gas storage chamber, making it suitable for energy storage facilities operating in high-frequency filling and discharging environments and high ground pressure environments.

Description

Technical Field

[0001] This invention relates to the field of underground gas storage engineering technology, and in particular to a composite lining structure for underground gas storage chambers. Background Technology

[0002] Underground gas storage projects are an important component of the energy storage field, especially with broad application prospects in compressed gas storage and hydrogen storage. Among lined cavern gas storage structures, their advantages in site selection flexibility and pressure bearing capacity have gradually made them a commonly used gas storage method. However, this type of structure still faces several key technical challenges in actual operation.

[0003] Conventional lined rock cavern gas storage structures typically consist of a sealing layer, a concrete lining layer, a shotcrete layer, and surrounding rock, arranged sequentially from the inside out. During operation, frequent inflation and deflation operations subject the lining structure to repeated pressure from both the internal gas and the external surrounding rock, making it highly susceptible to fatigue damage and localized stress concentration in the materials. Over time, these issues can lead to lining cracking, sealing failure, and even a decrease in overall structural stability, limiting further increases in gas storage pressure and the safe operation of the system.

[0004] While existing technologies have achieved some success in sealing performance and initial support, they still fall short in effectively mitigating structural damage caused by the combined effects of high pressure and cyclic loads. In particular, the lack of effective stress buffering and deformation coordination mechanisms between lining layers makes the structure prone to brittle failure under high stress, making it difficult to meet the engineering requirements of high strength and long-term operation.

[0005] Therefore, in view of the shortcomings of existing lined gas storage structures in terms of compressive strength and fatigue resistance, there is an urgent need to propose a new composite lining structure for underground gas storage chambers. Summary of the Invention

[0006] The purpose of this invention is to provide a composite lining structure for underground gas storage chambers that can enhance overall compressive strength and extend service life while maintaining good sealing performance.

[0007] To achieve the above objectives, the present invention provides the following solution: a composite lining structure for an underground gas storage chamber, comprising, from the internal cavity of the chamber outwards: a steel lining sealing layer, arranged close to the inner wall of the chamber; a concrete lining layer, poured on the outside of the steel lining sealing layer to form the main load-bearing structure; a sliding layer, laid on the outside of the concrete lining layer; and a shotcrete layer, attached to the surface of the surrounding rock as initial support; wherein, a plurality of polyurethane sealants are embedded inside the concrete lining layer.

[0008] Furthermore, multiple polyurethane fillers are radially and evenly distributed around the circumference of the concrete lining layer.

[0009] Furthermore, the polyurethane sealant is made of rigid polyurethane foam.

[0010] Furthermore, the polyurethane sealant is formed by on-site pouring or prefabrication.

[0011] Furthermore, the number of polyurethane joint fillers is 6, which are evenly distributed circumferentially along the concrete lining layer.

[0012] Furthermore, the slip layer is configured to allow relative displacement between the concrete lining layer and the shotcrete layer.

[0013] Furthermore, the slip layer is made of a composite bitumen-based material.

[0014] Furthermore, the steel lining sealing layer is welded from high-performance steel plates.

[0015] Furthermore, the sprayed concrete layer is directly sprayed onto the surface of the surrounding rock.

[0016] Furthermore, the amount of polyurethane sealant is determined based on the chamber diameter, design internal pressure, and geological conditions.

[0017] Compared with the prior art, the present invention discloses at least the following beneficial effects: This invention discloses a composite lining structure for underground gas storage caverns, which features several improvements compared to traditional lined rock cavern gas storage structures. The structure incorporates a rigid polyurethane foam filling layer, which significantly enhances the overall compressive strength and load-bearing capacity of the structure. Simultaneously, the composite asphalt slip layer within the structure plays a crucial role in stress regulation, effectively protecting the main sealing structure and preventing stress concentration under cyclic loading.

[0018] Furthermore, rigid polyurethane foam, as a green and environmentally friendly building material, possesses both excellent physical properties and eco-friendly characteristics. It not only has good thermal insulation properties, reducing energy loss, but also offers multiple advantages such as environmental friendliness, energy conservation, and health benefits.

[0019] This composite lining structure, through reasonable material configuration and optimized structural design, achieves a balance between structural performance and environmental benefits, providing a reliable guarantee for the long-term safe operation of underground gas storage projects. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention; Figure 2 This is a partial enlarged view of an embodiment of the present invention; Figure 3 This is a distribution diagram of the concrete lining layer in an embodiment of the present invention; Figure 4 This is a distribution diagram of polyurethane sealant in an embodiment of the present invention; In the diagram: 1. Tunnels; 2. Steel lining sealing layer; 3. Concrete lining layer; 4. Polyurethane sealant; 5. Slip layer; 6. Shotcrete; 7. Surrounding rock. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] like Figures 1 to 4 As shown, this embodiment of the invention provides a composite lining structure for underground gas storage chambers, which is particularly suitable for underground energy storage facilities that can withstand high-frequency gas filling and discharging cycles and high ground pressure environments, such as compressed gas storage or hydrogen storage facilities.

[0025] Specifically, the composite lining structure of the underground gas storage chamber, extending from the internal cavity of chamber 1 outwards to the surrounding rock 7, sequentially includes: a steel lining sealing layer 2, a concrete lining layer 3, a slip layer 5, and shotcrete 6. The concrete lining layer 3 contains several polyurethane sealants 4. These layered structures are tightly combined to form a functionally complementary and synergistic organic whole.

[0026] In this embodiment of the invention, the steel-lined sealing layer 2 is arranged close to the inner wall of the chamber 1. Its main function is to reliably seal the gas inside the chamber 1, prevent gas leakage, and ensure the airtightness and safety of the gas storage system. The steel-lined sealing layer 2 is typically welded from high-performance steel plates, forming the first and most critical barrier to prevent leakage of stored gas.

[0027] In this embodiment of the invention, the concrete lining layer 3 is poured on the outside of the steel lining sealing layer 2, forming the main load-bearing structure that withstands ground pressure and internal gas pressure. To improve the mechanical properties of the concrete lining layer 3, multiple polyurethane sealant joints 4 are pre-installed inside it as expansion joints.

[0028] In one specific embodiment, such as Figure 3 and Figure 4 As shown, six polyurethane sealants (4) are radially and evenly distributed around the entire circumference of the lining, forming a regular "sandwich" or "layered" structure with the concrete material. Polyurethane sealants (4) not only function as expansion joints but also, through their excellent flexibility and compressive strength, improve the overall stress characteristics of the lining, effectively disperse local stress, and inhibit the generation and development of concrete cracks, thereby enhancing the durability of the structure under high pressure and cyclic loading conditions.

[0029] Further optimizing the scheme, the polyurethane sealant 4 is made of rigid polyurethane foam, either cast on-site or prefabricated and then installed. Rigid polyurethane foam possesses good toughness, high compressive strength, and excellent closed-cell insulation properties. When embedded in concrete as sealant, it primarily serves three functions: First, as a stress dissipation channel, it effectively absorbs and disperses concentrated stress generated by internal and external pressures, thereby inhibiting the initiation and propagation of microcracks within the concrete; second, its inherent elasticity can adapt to minor deformations of the structure under load, improving the overall fatigue resistance of the lining; third, its insulation properties help mitigate the thermal shock to the concrete structure caused by drastic temperature fluctuations during gas injection and extraction.

[0030] A slip layer 5 is laid between the concrete lining layer 3 and the shotcrete 6. In one specific embodiment, the slip layer 5 is made of a composite asphalt material, which is a well-established material for interface isolation and stress buffering. The core function of the slip layer 5 is to provide an interface that allows for relative displacement, thereby balancing or "decoupling" the constraint forces generated between the primary support (shotcrete 6) and the secondary lining (concrete lining layer 3) due to stiffness differences and uneven deformation. By releasing this constraint stress, the slip layer 5 can significantly reduce the shear stress at the interface between the two, preventing structural cracks in the concrete layer due to stress concentration, which is crucial for coping with long-term cyclic gas extraction and venting operations.

[0031] The shotcrete layer 6 is attached to the surface of the surrounding rock 7 as an initial support structure, serving both as rock mass support during the excavation stage and providing a smooth base surface for subsequent lining construction. For example, in this embodiment, the shotcrete layer 6 can be directly sprayed onto the surface of the excavated surrounding rock 7 to quickly seal the rock surface and provide initial support.

[0032] The surrounding rock 7 is the final load-bearing medium of the entire structure. Through its coordinated stress with the lining system, it ensures the overall stability of the gas storage chamber.

[0033] In summary, this embodiment of the invention constructs an innovative composite lining system by introducing a built-in polyurethane sealant 4 and an independent sliding layer 5. Compared to the traditional simple composite structure of "sealing layer-concrete lining-shotcrete 6", this embodiment achieves a balance of rigidity and flexibility through the installation of flexible functional layers in key areas. This not only effectively enhances the ultimate pressure-bearing capacity of the chamber 1 structure but also significantly strengthens its resistance to fatigue damage caused by cyclic loading, thereby extending the safe service life of the gas storage facility.

[0034] It should be noted that although this embodiment uses six radial polyurethane sealants 4 as an example, in actual engineering applications, the specific number, cross-sectional shape, and size of the sealants can be adaptively adjusted according to the actual diameter of the chamber 1, the designed internal pressure, and the results of geological surveys. Such modifications should also be considered to fall within the protection scope of this invention.

[0035] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0036] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A composite lining structure for an underground gas storage chamber, characterized in that, From the internal cavity of chamber (1) outwards, it includes the following: The steel-lined sealing layer (2) is arranged close to the inner wall of the chamber (1); The concrete lining layer (3) is poured on the outside of the steel lining sealing layer (2) to form the main load-bearing structure; Slip layer (5) is laid on the outside of the concrete lining layer (3); A shotcrete (6) layer is attached to the surface of the surrounding rock (7) as initial support; wherein, a number of polyurethane fillers (4) are embedded inside the concrete lining layer (3).

2. The composite lining structure for underground gas storage chambers according to claim 1, characterized in that, Multiple polyurethane sealants (4) are radially and evenly distributed around the circumference of the concrete lining layer (3).

3. The composite lining structure for underground gas storage chambers according to claim 1 or 2, characterized in that, The polyurethane sealant (4) is made of rigid polyurethane foam.

4. The composite lining structure for underground gas storage chambers according to claim 3, characterized in that, The polyurethane sealant (4) is formed by on-site pouring or prefabrication.

5. The composite lining structure for underground gas storage chambers according to claim 2, characterized in that, The number of polyurethane sealant (4) is 6, which are evenly distributed circumferentially along the concrete lining layer (3).

6. The composite lining structure for underground gas storage chambers according to claim 1, characterized in that, The slip layer (5) is configured to allow relative displacement between the concrete lining layer (3) and the shotcrete layer (6).

7. The composite lining structure for underground gas storage chambers according to claim 1 or 6, characterized in that, The slip layer (5) is made of composite asphalt material.

8. The composite lining structure for underground gas storage chambers according to claim 1, characterized in that, The steel lining sealing layer (2) is welded from high-performance steel plates.

9. The composite lining structure for underground gas storage chambers according to claim 1, characterized in that, The sprayed concrete (6) layer is sprayed directly onto the surface of the surrounding rock (7).

10. The composite lining structure for underground gas storage chambers according to claim 1, characterized in that, The quantity of polyurethane sealant (4) is determined based on the diameter of the chamber (1), the designed internal pressure, and the geological conditions.

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